foo.c: In function 'main':
foo.c:7:15: error: expected ')' before numeric constant
    7 |         x = (x 20)+ 1
      |             ~ ^~~
      |               )
foo.c:7:22: error: expected ';' before 'printf'
    7 |         x = (x 20)+ 1
      |                      ^
      |                      ;
    8 | 
    9 |     printf("请输入转换的数和进:\n");
      |     ~~~~~~            
foo.c:27:1: warning: implicit declaration of function 'system' [-Wimplicit-function-declaration]
   27 | system("pause");
      | ^~~~~~

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